The formation of cancer is normally accompanied by changes in metabolic features of neoplastic tissue when compared with normal tissue. Thus it is our belief that the development of radiopharmaceuticals with specific metabolic processes will lead to determining the functional status and morphology of organs containing neoplastic diseases prior to, during and after treatment by monitoring externally physiological parameters of tissue metabolism. The main objective of this research proposal remains the same and is the development of radiopharmaceuticals bearing positron radiodiagnostic agents for imaging organs containing neoplastic diseases. The radiopharmaceuticals of choice are metabolites such as amino acids and sugars or their analogs. Our results (18F-2 and 3 fluoro-deoxy-D-glucose, 13N-glutamate and 13N-asaparagine) indicate that this approach is useful. A thorough evaluation of distribution and imaging of the radiopharmaceuticals developed or under development in tumor animals will be completed.